/* package whatever; // don't place package name! */
import java.util.*;
import java.lang.*;
import java.io.*;
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
{
Scanner scanner
= new Scanner
(System.
in); int N = scanner.nextInt();
for (int d = 2; d < N / d; d++) {
if (N % d == 0) {
N = d;
break;
}
}
out.print(N);
out.flush();
}
}
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